WEDNESDAY, June 20 (HealthDay News) -- Seven years after they underwent weight-loss surgery, patients as a whole fared better on several measurements of their risk of cardiac problems, a new study finds, and many returned to normal levels.

The findings don't prove that weight-loss surgery reduces the risk of events such as heart attack and stroke, although other research has suggested it does. And weight-loss surgery, which includes procedures such as gastric bypass, comes with major risks of its own and is only recommended for some severely obese patients.

Still, the findings suggested the procedure provided plenty of cardiac benefit to the patients, said study co-author Dr. John Morton, director of bariatric surgery and surgical quality at Stanford University School of Medicine. "For most of them, they came back to normal," he said. "There were roughly about a dozen measurements altogether, and there were substantial improvements across the board."

Weight-loss surgery, also known as bariatric surgery, aims to help severely obese people lose weight by shrinking the amount of food that their digestive systems can handle. The cost of the procedures ranges from $20,000 to $25,000, according to the Weight-Control Information Network of the U.S. National Institutes of Health.

A Swedish study published in January in the Journal of the American Medical Association suggested that the procedure reduces the risk of death from heart attack. Obese people who had the procedure were less likely than similar people to die from a cardiovascular problem (such as a heart attack) or suffer a first-time heart attack or stroke.

The new study looked at several measurements that indicate whether a person is at higher risk of cardiac problems, including levels of "bad" LDL and "good" HDL cholesterol, triglycerides and a specific protein.

The researchers tracked 182 patients -- mostly women, average age 44 years -- and managed to keep tabs on 78 of them for seven years. After seven years, the average patient weight fell from 286 pounds to 205 pounds. Their average cholesterol reading dipped from 184 to 174, LDL cholesterol dropped from 113 to 92, and triglycerides fell from 151 to 87.

On average, patients had big drops in a measurement of high-sensitivity C-reactive protein, the investigators found. People with high levels of this protein are at greater risk of heart attack and stroke.

The research is important because it tracks the effects of weight-loss surgery over several years, said Dr. Robin Blackstone, president of the American Society for Metabolic and Bariatric Surgery. The procedures may help patients reduce risk through weight loss and an accompanying change in the body's metabolism and the related workings of the heart, she said.

Lona Sandon, an assistant professor of clinical nutrition at the University of Texas Southwestern Medical Center at Dallas, cautioned that weight-loss surgery has pros and cons.

While it can help people lose weight fairly quickly, "which is important for people who are at high risk, such as those with heart disease and uncontrolled diabetes," the surgeries can cause complications, such as infections, she said. "Also, it can lead to malnutrition, as the amount of food someone can eat is very restricted and because part of the intestine is bypassed, meaning some nutrients cannot be absorbed."

The study is scheduled to be presented Wednesday at the annual meeting of the American Society for Metabolic and Bariatric Surgery, in San Diego. The data and conclusions should be viewed as preliminary until published in a peer-reviewed journal.